Considerable attention has focused on amphetamine-like stimulants largely because of their alarming abuse potential and profound clinical effects. The research outlined in this proposal will rely on a systematic analysis of the complete multiphasic response pattern produced by amphetamine, including a concurrent evaluation of locomotion and focused stereotyped behaviors, to further elucidate the neurochemical systems and processes underlying the behavioral response to acute and long-term administration of this drug. Evidence for the involvement of specific neuronal pathways will be sought by manipulating brain levels of catecholamines and serotonin and by local infusions of amphetamine and related compounds directly into the brains of freely moving animals. Corresponding changes in monoamine release and in the activity of monoamine-containing neurons produced by systemic and central infusions of amphetamine will provide additional information regarding the neuronal mechanisms mediating the behavioral response to this and related drugs of abuse.